diff options
Diffstat (limited to 'drivers/iio/adc/ad7768-1.c')
| -rw-r--r-- | drivers/iio/adc/ad7768-1.c | 652 |
1 files changed, 652 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c new file mode 100644 index 000000000..4afa50e5c --- /dev/null +++ b/drivers/iio/adc/ad7768-1.c @@ -0,0 +1,652 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Analog Devices AD7768-1 SPI ADC driver + * + * Copyright 2017 Analog Devices Inc. + */ +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/sysfs.h> +#include <linux/spi/spi.h> + +#include <linux/iio/buffer.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/trigger.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/trigger_consumer.h> + +/* AD7768 registers definition */ +#define AD7768_REG_CHIP_TYPE 0x3 +#define AD7768_REG_PROD_ID_L 0x4 +#define AD7768_REG_PROD_ID_H 0x5 +#define AD7768_REG_CHIP_GRADE 0x6 +#define AD7768_REG_SCRATCH_PAD 0x0A +#define AD7768_REG_VENDOR_L 0x0C +#define AD7768_REG_VENDOR_H 0x0D +#define AD7768_REG_INTERFACE_FORMAT 0x14 +#define AD7768_REG_POWER_CLOCK 0x15 +#define AD7768_REG_ANALOG 0x16 +#define AD7768_REG_ANALOG2 0x17 +#define AD7768_REG_CONVERSION 0x18 +#define AD7768_REG_DIGITAL_FILTER 0x19 +#define AD7768_REG_SINC3_DEC_RATE_MSB 0x1A +#define AD7768_REG_SINC3_DEC_RATE_LSB 0x1B +#define AD7768_REG_DUTY_CYCLE_RATIO 0x1C +#define AD7768_REG_SYNC_RESET 0x1D +#define AD7768_REG_GPIO_CONTROL 0x1E +#define AD7768_REG_GPIO_WRITE 0x1F +#define AD7768_REG_GPIO_READ 0x20 +#define AD7768_REG_OFFSET_HI 0x21 +#define AD7768_REG_OFFSET_MID 0x22 +#define AD7768_REG_OFFSET_LO 0x23 +#define AD7768_REG_GAIN_HI 0x24 +#define AD7768_REG_GAIN_MID 0x25 +#define AD7768_REG_GAIN_LO 0x26 +#define AD7768_REG_SPI_DIAG_ENABLE 0x28 +#define AD7768_REG_ADC_DIAG_ENABLE 0x29 +#define AD7768_REG_DIG_DIAG_ENABLE 0x2A +#define AD7768_REG_ADC_DATA 0x2C +#define AD7768_REG_MASTER_STATUS 0x2D +#define AD7768_REG_SPI_DIAG_STATUS 0x2E +#define AD7768_REG_ADC_DIAG_STATUS 0x2F +#define AD7768_REG_DIG_DIAG_STATUS 0x30 +#define AD7768_REG_MCLK_COUNTER 0x31 + +/* AD7768_REG_POWER_CLOCK */ +#define AD7768_PWR_MCLK_DIV_MSK GENMASK(5, 4) +#define AD7768_PWR_MCLK_DIV(x) FIELD_PREP(AD7768_PWR_MCLK_DIV_MSK, x) +#define AD7768_PWR_PWRMODE_MSK GENMASK(1, 0) +#define AD7768_PWR_PWRMODE(x) FIELD_PREP(AD7768_PWR_PWRMODE_MSK, x) + +/* AD7768_REG_DIGITAL_FILTER */ +#define AD7768_DIG_FIL_FIL_MSK GENMASK(6, 4) +#define AD7768_DIG_FIL_FIL(x) FIELD_PREP(AD7768_DIG_FIL_FIL_MSK, x) +#define AD7768_DIG_FIL_DEC_MSK GENMASK(2, 0) +#define AD7768_DIG_FIL_DEC_RATE(x) FIELD_PREP(AD7768_DIG_FIL_DEC_MSK, x) + +/* AD7768_REG_CONVERSION */ +#define AD7768_CONV_MODE_MSK GENMASK(2, 0) +#define AD7768_CONV_MODE(x) FIELD_PREP(AD7768_CONV_MODE_MSK, x) + +#define AD7768_RD_FLAG_MSK(x) (BIT(6) | ((x) & 0x3F)) +#define AD7768_WR_FLAG_MSK(x) ((x) & 0x3F) + +enum ad7768_conv_mode { + AD7768_CONTINUOUS, + AD7768_ONE_SHOT, + AD7768_SINGLE, + AD7768_PERIODIC, + AD7768_STANDBY +}; + +enum ad7768_pwrmode { + AD7768_ECO_MODE = 0, + AD7768_MED_MODE = 2, + AD7768_FAST_MODE = 3 +}; + +enum ad7768_mclk_div { + AD7768_MCLK_DIV_16, + AD7768_MCLK_DIV_8, + AD7768_MCLK_DIV_4, + AD7768_MCLK_DIV_2 +}; + +enum ad7768_dec_rate { + AD7768_DEC_RATE_32 = 0, + AD7768_DEC_RATE_64 = 1, + AD7768_DEC_RATE_128 = 2, + AD7768_DEC_RATE_256 = 3, + AD7768_DEC_RATE_512 = 4, + AD7768_DEC_RATE_1024 = 5, + AD7768_DEC_RATE_8 = 9, + AD7768_DEC_RATE_16 = 10 +}; + +struct ad7768_clk_configuration { + enum ad7768_mclk_div mclk_div; + enum ad7768_dec_rate dec_rate; + unsigned int clk_div; + enum ad7768_pwrmode pwrmode; +}; + +static const struct ad7768_clk_configuration ad7768_clk_config[] = { + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_8, 16, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_16, 32, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_32, 64, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_64, 128, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_128, 256, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_4, AD7768_DEC_RATE_128, 512, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_4, AD7768_DEC_RATE_256, 1024, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_4, AD7768_DEC_RATE_512, 2048, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_4, AD7768_DEC_RATE_1024, 4096, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_8, AD7768_DEC_RATE_1024, 8192, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_16, AD7768_DEC_RATE_1024, 16384, AD7768_ECO_MODE }, +}; + +static const struct iio_chan_spec ad7768_channels[] = { + { + .type = IIO_VOLTAGE, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), + .indexed = 1, + .channel = 0, + .scan_index = 0, + .scan_type = { + .sign = 'u', + .realbits = 24, + .storagebits = 32, + .shift = 8, + .endianness = IIO_BE, + }, + }, +}; + +struct ad7768_state { + struct spi_device *spi; + struct regulator *vref; + struct mutex lock; + struct clk *mclk; + unsigned int mclk_freq; + unsigned int samp_freq; + struct completion completion; + struct iio_trigger *trig; + struct gpio_desc *gpio_sync_in; + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + */ + union { + struct { + __be32 chan; + s64 timestamp; + } scan; + __be32 d32; + u8 d8[2]; + } data ____cacheline_aligned; +}; + +static int ad7768_spi_reg_read(struct ad7768_state *st, unsigned int addr, + unsigned int len) +{ + unsigned int shift; + int ret; + + shift = 32 - (8 * len); + st->data.d8[0] = AD7768_RD_FLAG_MSK(addr); + + ret = spi_write_then_read(st->spi, st->data.d8, 1, + &st->data.d32, len); + if (ret < 0) + return ret; + + return (be32_to_cpu(st->data.d32) >> shift); +} + +static int ad7768_spi_reg_write(struct ad7768_state *st, + unsigned int addr, + unsigned int val) +{ + st->data.d8[0] = AD7768_WR_FLAG_MSK(addr); + st->data.d8[1] = val & 0xFF; + + return spi_write(st->spi, st->data.d8, 2); +} + +static int ad7768_set_mode(struct ad7768_state *st, + enum ad7768_conv_mode mode) +{ + int regval; + + regval = ad7768_spi_reg_read(st, AD7768_REG_CONVERSION, 1); + if (regval < 0) + return regval; + + regval &= ~AD7768_CONV_MODE_MSK; + regval |= AD7768_CONV_MODE(mode); + + return ad7768_spi_reg_write(st, AD7768_REG_CONVERSION, regval); +} + +static int ad7768_scan_direct(struct iio_dev *indio_dev) +{ + struct ad7768_state *st = iio_priv(indio_dev); + int readval, ret; + + reinit_completion(&st->completion); + + ret = ad7768_set_mode(st, AD7768_ONE_SHOT); + if (ret < 0) + return ret; + + ret = wait_for_completion_timeout(&st->completion, + msecs_to_jiffies(1000)); + if (!ret) + return -ETIMEDOUT; + + readval = ad7768_spi_reg_read(st, AD7768_REG_ADC_DATA, 3); + if (readval < 0) + return readval; + /* + * Any SPI configuration of the AD7768-1 can only be + * performed in continuous conversion mode. + */ + ret = ad7768_set_mode(st, AD7768_CONTINUOUS); + if (ret < 0) + return ret; + + return readval; +} + +static int ad7768_reg_access(struct iio_dev *indio_dev, + unsigned int reg, + unsigned int writeval, + unsigned int *readval) +{ + struct ad7768_state *st = iio_priv(indio_dev); + int ret; + + mutex_lock(&st->lock); + if (readval) { + ret = ad7768_spi_reg_read(st, reg, 1); + if (ret < 0) + goto err_unlock; + *readval = ret; + ret = 0; + } else { + ret = ad7768_spi_reg_write(st, reg, writeval); + } +err_unlock: + mutex_unlock(&st->lock); + + return ret; +} + +static int ad7768_set_dig_fil(struct ad7768_state *st, + enum ad7768_dec_rate dec_rate) +{ + unsigned int mode; + int ret; + + if (dec_rate == AD7768_DEC_RATE_8 || dec_rate == AD7768_DEC_RATE_16) + mode = AD7768_DIG_FIL_FIL(dec_rate); + else + mode = AD7768_DIG_FIL_DEC_RATE(dec_rate); + + ret = ad7768_spi_reg_write(st, AD7768_REG_DIGITAL_FILTER, mode); + if (ret < 0) + return ret; + + /* A sync-in pulse is required every time the filter dec rate changes */ + gpiod_set_value(st->gpio_sync_in, 1); + gpiod_set_value(st->gpio_sync_in, 0); + + return 0; +} + +static int ad7768_set_freq(struct ad7768_state *st, + unsigned int freq) +{ + unsigned int diff_new, diff_old, pwr_mode, i, idx; + int res, ret; + + diff_old = U32_MAX; + idx = 0; + + res = DIV_ROUND_CLOSEST(st->mclk_freq, freq); + + /* Find the closest match for the desired sampling frequency */ + for (i = 0; i < ARRAY_SIZE(ad7768_clk_config); i++) { + diff_new = abs(res - ad7768_clk_config[i].clk_div); + if (diff_new < diff_old) { + diff_old = diff_new; + idx = i; + } + } + + /* + * Set both the mclk_div and pwrmode with a single write to the + * POWER_CLOCK register + */ + pwr_mode = AD7768_PWR_MCLK_DIV(ad7768_clk_config[idx].mclk_div) | + AD7768_PWR_PWRMODE(ad7768_clk_config[idx].pwrmode); + ret = ad7768_spi_reg_write(st, AD7768_REG_POWER_CLOCK, pwr_mode); + if (ret < 0) + return ret; + + ret = ad7768_set_dig_fil(st, ad7768_clk_config[idx].dec_rate); + if (ret < 0) + return ret; + + st->samp_freq = DIV_ROUND_CLOSEST(st->mclk_freq, + ad7768_clk_config[idx].clk_div); + + return 0; +} + +static ssize_t ad7768_sampling_freq_avail(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7768_state *st = iio_priv(indio_dev); + unsigned int freq; + int i, len = 0; + + for (i = 0; i < ARRAY_SIZE(ad7768_clk_config); i++) { + freq = DIV_ROUND_CLOSEST(st->mclk_freq, + ad7768_clk_config[i].clk_div); + len += scnprintf(buf + len, PAGE_SIZE - len, "%d ", freq); + } + + buf[len - 1] = '\n'; + + return len; +} + +static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(ad7768_sampling_freq_avail); + +static int ad7768_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long info) +{ + struct ad7768_state *st = iio_priv(indio_dev); + int scale_uv, ret; + + switch (info) { + case IIO_CHAN_INFO_RAW: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + + ret = ad7768_scan_direct(indio_dev); + if (ret >= 0) + *val = ret; + + iio_device_release_direct_mode(indio_dev); + if (ret < 0) + return ret; + + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + scale_uv = regulator_get_voltage(st->vref); + if (scale_uv < 0) + return scale_uv; + + *val = (scale_uv * 2) / 1000; + *val2 = chan->scan_type.realbits; + + return IIO_VAL_FRACTIONAL_LOG2; + + case IIO_CHAN_INFO_SAMP_FREQ: + *val = st->samp_freq; + + return IIO_VAL_INT; + } + + return -EINVAL; +} + +static int ad7768_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long info) +{ + struct ad7768_state *st = iio_priv(indio_dev); + + switch (info) { + case IIO_CHAN_INFO_SAMP_FREQ: + return ad7768_set_freq(st, val); + default: + return -EINVAL; + } +} + +static struct attribute *ad7768_attributes[] = { + &iio_dev_attr_sampling_frequency_available.dev_attr.attr, + NULL +}; + +static const struct attribute_group ad7768_group = { + .attrs = ad7768_attributes, +}; + +static const struct iio_info ad7768_info = { + .attrs = &ad7768_group, + .read_raw = &ad7768_read_raw, + .write_raw = &ad7768_write_raw, + .debugfs_reg_access = &ad7768_reg_access, +}; + +static int ad7768_setup(struct ad7768_state *st) +{ + int ret; + + /* + * Two writes to the SPI_RESET[1:0] bits are required to initiate + * a software reset. The bits must first be set to 11, and then + * to 10. When the sequence is detected, the reset occurs. + * See the datasheet, page 70. + */ + ret = ad7768_spi_reg_write(st, AD7768_REG_SYNC_RESET, 0x3); + if (ret) + return ret; + + ret = ad7768_spi_reg_write(st, AD7768_REG_SYNC_RESET, 0x2); + if (ret) + return ret; + + st->gpio_sync_in = devm_gpiod_get(&st->spi->dev, "adi,sync-in", + GPIOD_OUT_LOW); + if (IS_ERR(st->gpio_sync_in)) + return PTR_ERR(st->gpio_sync_in); + + /* Set the default sampling frequency to 32000 kSPS */ + return ad7768_set_freq(st, 32000); +} + +static irqreturn_t ad7768_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct ad7768_state *st = iio_priv(indio_dev); + int ret; + + mutex_lock(&st->lock); + + ret = spi_read(st->spi, &st->data.scan.chan, 3); + if (ret < 0) + goto err_unlock; + + iio_push_to_buffers_with_timestamp(indio_dev, &st->data.scan, + iio_get_time_ns(indio_dev)); + +err_unlock: + iio_trigger_notify_done(indio_dev->trig); + mutex_unlock(&st->lock); + + return IRQ_HANDLED; +} + +static irqreturn_t ad7768_interrupt(int irq, void *dev_id) +{ + struct iio_dev *indio_dev = dev_id; + struct ad7768_state *st = iio_priv(indio_dev); + + if (iio_buffer_enabled(indio_dev)) + iio_trigger_poll(st->trig); + else + complete(&st->completion); + + return IRQ_HANDLED; +}; + +static int ad7768_buffer_postenable(struct iio_dev *indio_dev) +{ + struct ad7768_state *st = iio_priv(indio_dev); + + /* + * Write a 1 to the LSB of the INTERFACE_FORMAT register to enter + * continuous read mode. Subsequent data reads do not require an + * initial 8-bit write to query the ADC_DATA register. + */ + return ad7768_spi_reg_write(st, AD7768_REG_INTERFACE_FORMAT, 0x01); +} + +static int ad7768_buffer_predisable(struct iio_dev *indio_dev) +{ + struct ad7768_state *st = iio_priv(indio_dev); + + /* + * To exit continuous read mode, perform a single read of the ADC_DATA + * reg (0x2C), which allows further configuration of the device. + */ + return ad7768_spi_reg_read(st, AD7768_REG_ADC_DATA, 3); +} + +static const struct iio_buffer_setup_ops ad7768_buffer_ops = { + .postenable = &ad7768_buffer_postenable, + .predisable = &ad7768_buffer_predisable, +}; + +static const struct iio_trigger_ops ad7768_trigger_ops = { + .validate_device = iio_trigger_validate_own_device, +}; + +static void ad7768_regulator_disable(void *data) +{ + struct ad7768_state *st = data; + + regulator_disable(st->vref); +} + +static void ad7768_clk_disable(void *data) +{ + struct ad7768_state *st = data; + + clk_disable_unprepare(st->mclk); +} + +static int ad7768_probe(struct spi_device *spi) +{ + struct ad7768_state *st; + struct iio_dev *indio_dev; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + st->spi = spi; + + st->vref = devm_regulator_get(&spi->dev, "vref"); + if (IS_ERR(st->vref)) + return PTR_ERR(st->vref); + + ret = regulator_enable(st->vref); + if (ret) { + dev_err(&spi->dev, "Failed to enable specified vref supply\n"); + return ret; + } + + ret = devm_add_action_or_reset(&spi->dev, ad7768_regulator_disable, st); + if (ret) + return ret; + + st->mclk = devm_clk_get(&spi->dev, "mclk"); + if (IS_ERR(st->mclk)) + return PTR_ERR(st->mclk); + + ret = clk_prepare_enable(st->mclk); + if (ret < 0) + return ret; + + ret = devm_add_action_or_reset(&spi->dev, ad7768_clk_disable, st); + if (ret) + return ret; + + st->mclk_freq = clk_get_rate(st->mclk); + + spi_set_drvdata(spi, indio_dev); + mutex_init(&st->lock); + + indio_dev->channels = ad7768_channels; + indio_dev->num_channels = ARRAY_SIZE(ad7768_channels); + indio_dev->name = spi_get_device_id(spi)->name; + indio_dev->info = &ad7768_info; + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED; + + ret = ad7768_setup(st); + if (ret < 0) { + dev_err(&spi->dev, "AD7768 setup failed\n"); + return ret; + } + + st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d", + indio_dev->name, indio_dev->id); + if (!st->trig) + return -ENOMEM; + + st->trig->ops = &ad7768_trigger_ops; + st->trig->dev.parent = &spi->dev; + iio_trigger_set_drvdata(st->trig, indio_dev); + ret = devm_iio_trigger_register(&spi->dev, st->trig); + if (ret) + return ret; + + indio_dev->trig = iio_trigger_get(st->trig); + + init_completion(&st->completion); + + ret = devm_request_irq(&spi->dev, spi->irq, + &ad7768_interrupt, + IRQF_TRIGGER_RISING | IRQF_ONESHOT, + indio_dev->name, indio_dev); + if (ret) + return ret; + + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, + &iio_pollfunc_store_time, + &ad7768_trigger_handler, + &ad7768_buffer_ops); + if (ret) + return ret; + + return devm_iio_device_register(&spi->dev, indio_dev); +} + +static const struct spi_device_id ad7768_id_table[] = { + { "ad7768-1", 0 }, + {} +}; +MODULE_DEVICE_TABLE(spi, ad7768_id_table); + +static const struct of_device_id ad7768_of_match[] = { + { .compatible = "adi,ad7768-1" }, + { }, +}; +MODULE_DEVICE_TABLE(of, ad7768_of_match); + +static struct spi_driver ad7768_driver = { + .driver = { + .name = "ad7768-1", + .of_match_table = ad7768_of_match, + }, + .probe = ad7768_probe, + .id_table = ad7768_id_table, +}; +module_spi_driver(ad7768_driver); + +MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>"); +MODULE_DESCRIPTION("Analog Devices AD7768-1 ADC driver"); +MODULE_LICENSE("GPL v2"); |